The present invention relates to the field of radiation oncology and more specifically to a beamblock tray that can be used in multiple types of defining heads, and a coding system that ensures proper orientation of the tray.
Medical linear accelerators can be used to generate x-ray radiation for the treatment of cancer. While x-ray radiation can help to arrest or reverse the progression of cancer, x-rays are also capable of damaging healthy tissue. Therefore, during the course of radiation therapy, it is important to minimize the amount of radiation delivered to healthy tissue surrounding the cancerous tumor. FIG. 1 is a simple diagram of a medical linear accelerator 10. A defining head 12 is coupled to a supporting gantry 14. The defining head 14 holds an x-ray source 16 which is coupled to a beamblock tray 18. The beamblock tray is coupled to a control console 20 which includes software for providing a particular treatment plan for a patient.
One way to precisely shape the x-ray beam is to mount the beamblock tray 18 in between the x-ray source and the patient. X-ray impermeable shielding (not shown) can be molded into precise shapes and mounted onto the beamblock tray 18. In turn, the beamblock tray 16, together with the shielding, is mounted on the xe2x80x9cdefining headxe2x80x9d of the medical linear accelerator. In this way, x-ray radiation is delivered to the target tissue while minimizing the amount of radiation reaching neighboring tissue. This is a well-established method of shaping the x-ray beam.
FIG. 2 illustrates a conventional beamblock tray 18. The conventional beamblock tray 18 includes a coded connector 102 which is inserted in a slot of the defining head which allows the beamblock tray 18 to be utilized in a particular orientation. Software within the control console 20 (FIG. 1) provides the support for the coding scheme. The coded connector 102 in a preferred embodiment is a resistor pair combination which defines the treatment for a particular patient which is to receive the radiation.
Over the past 20 years, many new features have been introduced into the design of medical linear accelerators. As a consequence of these improvements, it has been necessary to make changes to the defining head, including the orientation of the slots in which the beamblock trays are inserted. As a result, radiation clinics that have been operating linear accelerators for several years may have some linear accelerators with one slot orientation and other linear accelerators with a different slot orientation. This can create a problem when a patient has to be treated on more than one linear accelerator (which might occur because of scheduling constraints, for example). In such cases, the clinic staff must prepare two beamblock traysxe2x80x94one for each slot orientationxe2x80x94to ensure that the beam field is correctly shaped in all of the linear accelerators. The disadvantages of preparing two trays are (a) the cost of the extra beamblock tray, (b) extra preparation time required by the clinical staff, (c) extra material involved in preparing the shielding, and (d) extra storage space for the second tray.
Accordingly, what is needed is a system and method for overcoming the above-identified problems. The present invention addresses such a need.
A beamblock tray for use with multiple defining heads within a medical linear accelerator is disclosed. The beamblock tray comprises a tray portion, and a plurality of coded connectors coupled to the tray portion The tray portion can be inserted into a defining head in a plurality of directions based upon the plurality of coded connectors.
A system and method in accordance with the present invention utilizes a plurality of coded connectors that can be used to identify a patient. In addition, the connectors and mounting flange are such that permits the tray to be inserted a plurality of directions. Finally, a coding system is provided that prevents radiation from being delivered if the tray is oriented incorrectly. A dual axis beamblock tray in accordance with the present invention circumvents this problem by a counting for the two possible orientations of beamblock tray holders, thereby permitting the radiation therapist to use a single tray with a variety of linear accelerators.